#!/usr/bin/env bash

#

# Initializes git submodules with authentication when any credential is

# available, and with bounded retry when none is. GitHub throttles anonymous

# git-over-HTTPS from the CI agents' shared egress IPs with intermittent

# 401s that git reports as:

# fatal: could not read Username for 'https://github.com': terminal prompts disabled

# even though every submodule repo is public.

#

# ci/git-auth-env.sh resolves the credential (GH_TOKEN, or the credential

# the checkout task persisted with persistCredentials: true) and exports it

# through GIT_CONFIG_{COUNT,KEY_0,VALUE_0}, which every spawned submodule

# clone/fetch inherits (the same mechanism the checkout task uses for its

# own submodule handling). Nothing is written to disk and nothing appears

# on a command line or in xtrace output (neither script uses `set -x`).

# With no credential at all the clone stays anonymous and relies on the

# retry: GitHub's anonymous throttle windows are short, so ~4 minutes of

# backoff outlasts a burst without stalling a healthy build, whereas git's

# own instant second attempt lands inside the same window and dies.

#

# Each attempt clones shallow (--depth 1) first: CI never needs submodule

# history, only the pinned tree. Several submodules pin a SHA that is not a

# branch tip; git then fetches that SHA directly, which github.com serves

# for any ref-reachable commit (uploadpack.allowReachableSHA1InWant) -- the

# same mechanism .gitmodules' existing shallow = true entries and every

# exact-SHA CI fetch already rely on. Because the git protocol does not

# guarantee that for arbitrary servers, a failed shallow pass falls back to

# a full-history pass within the same attempt before any backoff.

#

# Usage: bash ci/submodule-update.sh [--recursive] <submodule-path>...

set -eu

recursive=""

if [[ "${1:-}" == "--recursive" ]]; then

recursive="--recursive"

shift

fi

if [[ $# -eq 0 ]]; then

echo "usage: bash ci/submodule-update.sh [--recursive] <submodule-path>..." >&2

exit 2

fi

eval "$(bash "$(dirname "$0")/git-auth-env.sh")"

update_args=(--init)

if [[ -n "$recursive" ]]; then

update_args+=(--recursive)

fi

# A failed `git submodule update` is safe to rerun: git removes the target

# directory of a failed clone, and submodules that already completed are

# skipped on the next pass.

for delay in 0 15 30 60 120; do

if [[ "$delay" -gt 0 ]]; then

echo "git submodule update failed; retrying in ${delay}s" >&2

sleep "$delay"

fi

if git submodule update "${update_args[@]}" --depth 1 "$@"; then

exit 0

fi

echo "shallow submodule update failed; trying full history" >&2

if git submodule update "${update_args[@]}" "$@"; then

exit 0

fi

done

echo "git submodule update failed after all retries" >&2

exit 1